Substance name: Cobalt (II) sulphate EC number - ECHA

Transcription

SVHC SUPPORT DOCUMENT
Substance name: Cobalt (II) sulphate
EC number: 233-334-2
CAS number: 10124-43-3
MEMBER STATE COMMITTEE
SUPPORT DOCUMENT FOR IDENTIFICATION OF
COBALT (II) SULPHATE
AS A SUBSTANCE OF VERY HIGH CONCERN BECAUSE OF
ITS CMR PROPERTIES
Adopted on 2 December 2010
1
CONTENTS
1 IDENTITY OF THE SUBSTANCE AND PHYSICAL AND CHEMICAL PROPERTIES .................................6
1.1 Name and other identifiers of the substance ...................................................................................................6
1.2 Composition of the substance .........................................................................................................................6
1.3 Physico-chemical properties ...........................................................................................................................7
2 HARMONISED CLASSIFICATION AND LABELLING ....................................................................................8
2.1 Classification according to Directive 67/548/EEC .........................................................................................8
2.2 Classification according to Regulation EC 1272/2008 ...................................................................................8
3 ENVIRONMENTAL FATE PROPERTIES...........................................................................................................10
4 HUMAN HEALTH HAZARD ASSESSMENT.....................................................................................................10
5 ENVIRONMENTAL HAZARD ASSESSMENT ..................................................................................................10
6 CONCLUSIONS ON THE SVHC PROPERTIES .................................................................................................11
6.1 PBT, vPvB assessment ...................................................................................................................................11
6.2 CMR assessment.............................................................................................................................................11
1 ANNEX I: HUMAN HEALTH HAZARD ASSESSMENT ..................................................................................15
1.1 Toxicokinetics (absorption, metabolism, distribution and elimination) .........................................................15
1.1.1 Non-human information ......................................................................................................................15
1.1.2 Human information .............................................................................................................................15
1.1.3 Summary and discussion on toxicokinetics.........................................................................................16
1.2 Acute toxicity .................................................................................................................................................16
1.3 Irritation ..........................................................................................................................................................16
1.4 Corrosivity......................................................................................................................................................16
1.5 Sensitisation....................................................................................................................................................17
1.6 Repeated dose toxicity....................................................................................................................................17
1.7 Mutagenicity...................................................................................................................................................17
1.7.2 Human data .........................................................................................................................................17
1.7.3 Other relevant information ..................................................................................................................18
1.7.4 Summary and discussion of mutagenicity ...........................................................................................21
1.8 Carcinogenicity...............................................................................................................................................21
1.8.2 Human information .............................................................................................................................23
1.8.4 Summary and discussion of carcinogenicity .......................................................................................26
2
1.9 Toxicity for reproduction................................................................................................................................26
1.9.1 Effects on fertility................................................................................................................................26
1.9.3 Developmental toxicity .......................................................................................................................27
1.9.5 Summary and discussion of reproductive toxicity...............................................................................29
1.10 Other effects ...................................................................................................................................................29
2 ANNEX II: ANIMAL CARCINOGENICITY AND RELATED EFFECTS DATA OF OTHER COBALT
COMPOUNDS. ............................................................................................................................................................30
TABLES
Table 1: Substance identity................................................................................................................................................. 6
Table 2: Overview of physicochemical properties ............................................................................................................. 7
3
Substance Name:
Cobalt(II)sulphate
EC Number:
233-334-2
CAS number:
10124-43-3
In addition, this support document covers also the hydrated forms of Cobalt(II)sulphate1.
•
The substance is identified as substance meeting the criteria of Article 57 (a) of Regulation (EC)
1907/2006 (REACH) owing to its classification in the hazard class carcinogenicity category 1B2
under Annex VI, part 3, Table 3.1 of Regulation (EC) No 1272/2008, as well as its
corresponding classification under Annex VI, part 3, Table 3.2 as carcinogen category 23.
•
The substance is identified as substance meeting the criteria of Article 57 (c) of Regulation (EC)
1907/2006 (REACH) owing to its classification in the hazard class reproductive toxicity
category 1B2 under Annex VI, part 3, Table 3.1 of Regulation (EC) No 1272/2008 as well as its
corresponding classification under Annex VI, part 3, Table 3.2 of Regulation (EC) No
1272/2008 as toxic for reproduction category 23.
Summary of how the substance meets the Carcinogen 1B and Reprotox 1B criteria
Prior to 1 December 2010 Articles 57 (a) and (c) of REACH required that substances may be
included in Annex XIV if they meet the criteria for classification as (a) carcinogenic category 1 or 2
and (c) toxic for reproduction category 1 or 2, in accordance with Directive 67/548/EEC.
As of 1 December 2010 Articles 57(a) and (c) of REACH have been amended by Regulation (EC)
No 1272/2008 in so far as they provide that substances may be included in Annex XIV where the
substances meet the criteria for classification in (a) the hazard class carcinogenicity category 1A or
1B in accordance with section 3.6 of Annex I to Regulation (EC) no. 1272/2008 and (c) the hazard
class reproductive toxicity category 1A or 1B, adverse effects on sexual function and fertility or on
development in accordance with section 3.7 of Annex I to Regulation (EC) No 1272/2008.
The original Annex XV dossier of the Netherlands for Cobalt(II)sulphate was submitted before 1
December 2010 and therefore proposed that the substance is identified as meeting the criteria under
Article 57(a) and (c) of the version of REACH existing at that time, i.e., the substance meets the
criteria for classification as carcinogen category 2 and toxic for reproduction category 2 set out
under Directive 67/548/EEC.
However, as the agreement of the Member State Committee in relation to the identification has been
taken after 1 December 2010, this agreement is based on the criteria set out in the amended Article
57. It should however be noted that the amendment of Article 57 was not sufficient to reopen the
1 According to the rules applied when establishing EINECS (Manual of Decisions, Criteria for reporting substances for EINECS,
http://ecb.jrc.ec.europa.eu/documents/New-Chemicals/Manual_of_decisions.pdf ): “The anhydrous form can be reported and will, by
implication, represent all hydrated forms.”
2 Classification in accordance with Regulation (EC) No 1272/2008 Annex VI, part 3, Table 3.1 List of harmonised classification and
labelling of hazardous substances as amended and adapted to technical and scientific progress by Commission Regulation (EC) No
790/2009, OJ No L 235, p. 1, 5.9.2009
3 Classification in accordance with Regulation (EC) No 1272/2008 Annex VI, part 3, Table 3.2 List of harmonised classification and
labelling of hazardous substances (from Annex I to Council Directive 67/548/EEC) as amended and adapted to technical and
scientific progress by Commission Regulation (EC) No 790/2009, OJ No L 235, p. 1, 5.9.2009
4
public consultation on the identification of this substance given that the harmonised classification
criteria correspond to the criteria for classifying and labelling substances under Directive
67/548/EEC.
Pursuant to Regulation (EC) No 1272/2008 as amended and adapted to technical and scientific
progress by Regulation (EC) No 790/2009, as of 1 December 2010, Cobalt(II)sulphate, is listed
under index number 027-005-00-0 in Annex VI, part 3, Table 3.1 (the list of harmonised
classification and labelling of hazardous substances) of Regulation (EC) No 1272/2008 as
carcinogen category 1B. Its corresponding classification in Annex VI, part 3, Table 3.2 (the list of
harmonised and classification and labelling of hazardous substances from Annex I to Directive
67/548/EEC) of Regulation (EC) No 1272/2008 is carcinogen category 2. The hydrous forms of
Cobalt(II)sulphate are also considered as carcinogens category 1B (corresponding to carcinogen
category 2) according to Annex VI, part 1.1.1.5, of Regulation (EC) No 1272/2008. According to
part 1.1.1.5 (Entries of group of substance) entries in part 3 for salts (under any denomination)
cover both anhydrous and hydrous forms, unless specified otherwise.
Therefore, this classification of the substance(s) in Regulation (EC) No 1272/2008 shows that the
substance meets the criteria for classification as carcinogen in accordance with Article 57 (a) of
REACH.
progress by Regulation (EC) No 790/2009, as of 1 December 2010, Cobalt(II)sulphate is listed
under index number 027-005-00-0 in Annex VI, part 3, Table 3.1 (the list of harmonised
classification and labelling of hazardous substances) of Regulation (EC) No 1272/2008 as toxic for
reproduction category 1B2. Its corresponding classification in Annex VI, part 3, Table 3.2 (the list
of harmonised and classification and labelling of hazardous substances from Annex I to Directive
67/548/EEC) of Regulation (EC) No 1272/2008 is toxic for reproduction category 23. All hydrous
forms of cobalt(II) sulphate are also considered as toxic for reproduction category 1B
(corresponding to toxic for reproduction category 2) according to Annex VI, part 1.1.1.5, of
Regulation (EC) No 1272/2008. According to part 1.1.1.5 (Entries of group of substance) entries in
part 3 for salts (under any denomination) cover both anhydrous and hydrous forms, unless specified
otherwise.
Therefore, this classification of the substance in Regulation (EC) No 1272/2008 shows that the
substance meets the criteria for classification as toxic for reproduction in accordance with Article 57
(c) of REACH.
5
JUSTIFICATION
1
IDENTITY OF THE SUBSTANCE AND PHYSICAL AND CHEMICAL
PROPERTIES
1.1
Name and other identifiers of the substance
Table 1: Substance identity
EC number:
233-334-2
EC name:
Cobalt sulphate
CAS number:
10124-43-3
CAS name:
Sulfuric acid, cobalt(2+) salt (1:1)
Index number in Annex VI of the CLP Regulation
027-005-00-0
Molecular formula:
Co.H2O4S
Molecular weight range:
154.99
Structural formula:
This support document covers also the hydrated forms of cobalt(II) sulphate. According to the rules
applied when establishing EINECS4: “The anhydrous form can be reported and will, by implication,
represent all hydrated forms.”
1.2
Composition of the substance
Information on concentration range and on any impurities is not known.
4 Manual of Decisions, Criteria for reporting substances for EINECS, http://ecb.jrc.ec.europa.eu/documents/NewChemicals/Manual_of_decisions.pdf
6
1.3
Physico-chemical properties
Table 2: Overview of physicochemical properties
Property
Value
Remarks
Physical state at 20°C and
101.3 kPa
Dark-bluish crystals
U.S., Department of Health and
Human Services
Melting/freezing point
735oC
Human Services
Water solubility
soluble
362 g/L at 20˚C
830 g/L at 100˚C
Not relevant
Human Services
Partition coefficient noctanol/water (log value)
7
2
HARMONISED CLASSIFICATION AND LABELLING
2.1
Classification according to Directive 67/548/EEC
Pursuant to the Regulation (EC) No 1272/2008 as amended and adapted to technical and scientific
progress by Regulation (EC) No 790/2009 as of 1 December 2010, Cobalt(II) sulphate is listed
under index number 027-005-00-05 in Annex VI, part 3, Table 3.2 of Regulation (EC) No
1272/2008 with the following classification:
Carc.Cat. 2; R49
Repr.Cat. 2; R60
Xn; R22
R42/43:
Muta.Cat. 3; R68
N; R50/53:
May cause cancer by inhalation
May impair fertility
Harmful if swallowed
May cause sensitization by inhalation and skin contact
Possible risk of irreversible effects
Very toxic to aquatic organisms, may cause long-term adverse effects in the
aquatic environment
Specific concentration limits:
Classification
Concentration
Carc. Cat. 2 R49
C ≥ 0.01%
N; R50-53
C ≥ 2.5%
N; R51-53
0.25% ≤ C < 2.5%
R52-53
0.025% ≤ C < 0.25%
Notes:
Note E:
Substances with specific effects on human health (see Chapter 4 of Annex VI to
Directive 67/548/EEC) that are classified as carcinogenic, mutagenic and/or toxic for reproduction
in categories 1 or 2 are ascribed Note E if they are also classified as very toxic (T+), toxic (T) or
harmful (Xn). For these substances, the risk phrases R20, R21, R22, R23, R24, R25, R26, R27,
R28, R39, R68 (harmful), R48 and R65 and all combinations of these risk phrases shall be preceded
by the word ‘Also’.
Note 1:
The concentration stated or, in the absence of such concentrations, the generic
concentrations of this Regulation (Table 3.1) or the generic concentrations of Directive 1999/45/EC
(Table 3.2) are the percentages by weight of the metallic element calculated with reference to the
total weight of the mixture.
2.2
Classification according to Regulation EC 1272/2008
progress by Regulation (EC) No 790/2009 as of 1 December 2010, Cobalt(II) sulphate is listed in
5 International Chemical Identification: cobalt sulphate
8
Annex VI, part 3, Table 3.1 of Regulation (EC) No. 1272/2008 (list of harmonised classification
and labelling of hazardous substances) with the following classification:
Carc. 1B, H350i
Muta. 2, H341
Repr. 1B, H360F***6
Acute Tox. 4*7, H302
Resp.Sens. 1 H334
Skin Sens.1 H317
Aquatic Acute 1 H400
Aquatic Chronic 1 H410
May cause cancer by inhalation
Suspected of causing genetic defects
May damage fertility
Harmful if swallowed
May cause allergy or asthma symptoms or breathing difficulties if
inhaled
May cause an allergic skin reaction
Very toxic to aquatic life
Very toxic to aquatic life with long lasting effects
Specific concentration limits:
Classification
Concentration
Carc. 1B H350i
C ≥ 0.01%
M-factor: 10
Notes:
Note 1:
The concentration stated or, in the absence of such concentrations, the generic
concentrations of this Regulation (Table 3.1) or the generic concentrations of Directive 1999/45/EC
(Table 3.2) are the percentages by weight of the metallic element calculated with reference to the
total weight of the mixture.
6 According to Annex VI (Part 1, entry 1.2.3): H360 and H361 indicate a general concern for effects on both fertility and
development: ‘May damage/Suspected fertility or the unborn child’. According to the criteria, the general hazard statement can be
replaced by the hazard statement indicating only the property of concern, where either fertility or developmental effects are proven to
be not relevant. In order not to lose information from the harmonised classifications for fertility and developmental effects under
Directive 67/548/EEC, the classifications have been translated only for those effects classified under that Directive. These hazards
statements are indicated by reference *** in Table 3.1.
7 The reference (*) indicates minimum classification.
9
3
ENVIRONMENTAL FATE PROPERTIES
Not relevant for this type of dossier.
4
HUMAN HEALTH HAZARD ASSESSMENT
Information on the hazard properties of cobalt(II)sulphate and its hydrates is provided for
information purposes only as the classification has already been concluded by TC-C&L and
included in Annex VI. Please refer to Annex I of this report.
5
ENVIRONMENTAL HAZARD ASSESSMENT
10
6
CONCLUSIONS ON THE SVHC PROPERTIES
6.1
PBT, vPvB assessment
6.2
CMR assessment
The classification of Cobalt(II)sulphate (anhydrous and hydrous forms) in Regulation (EC) No
1272/2008 as amended and adapted to technical and scientific progress by Regulation (EC) No
790/2009 (Carc. 1B; H350i: “May cause cancer by inhalation” that corresponds to classification
Carc.Cat. 2; R49: “May cause cancer by inhalation”) shows that the substance meets the criteria for
classification as carcinogen in accordance with Article 57 (a) of REACH.
Furthermore, the classification of Cobalt(II)sulphate (anhydrous and hydrous forms) in Regulation
(EC) No 1272/2008 as amended and adapted to technical and scientific progress by Regulation (EC)
No 790/2009 (Repr. 1B; H360F***: “May damage fertility” that corresponds to classification
Repr.Cat. 2; R60: “May impair fertility”) shows that the substance meets the criteria for
classification as toxic for reproduction in accordance with Article 57 (c) of REACH.
11
REFERENCES
ASTDR (2004). Toxicological profile for cobalt. Atlanta, GA. United States Department of Health and
Human Services, Public Health Services, Agency for Toxic Substances and Disease Registry.
ASTDR (2001). Toxicological profile for cobalt. Atlanta, GA. United States Department of Health and
Human Services, Public Health Services, Agency for Toxic Substances and Disease Registry.
ATSDR (2010). Minimal Risk Levels for hazardous substances. http://www.atsdr.cdc.gov/mrls/index.html
Bucher JR, Elwell MR, Thompson MB, Chou BJ, Renne R, Ragan HA (1990) Inhalation toxicity studies of
cobalt sulphate in F344/N rats and B6C3F1 mice. Fundamental and Applied Toxicology, 15:357–372.
Bucher JR, Hailey JR, Roycroft JR, Haseman JK, Sills RC, Grumbein SL, Mellick PW, Chou BJ (1999)
Inhalation toxicity and carcinogenicity studies of cobalt sulphate. Toxicological Sciences, 49:56–67.
ECB (2005). Joint Research Centre. Institute for Health and Consumer Protection. Unit: Toxicology and
Chemical Substances. Meeting of the technical committee C&L on the classification and labelling of
dangerous substances. Summary record: ECBI/139/04 Rev. 2. Available from:
http://tcsweb3.jrc.it/DOCUMENTS/ClassificationLabelling/ADOPTED_SUMMARY_RECORDS/13904r2_sr_TC_C&L_Health_0904.pdf
Elbetieha A., Al-Thani A.S., Al-Thani R.K., Darmani H. & Owais W. (2004) Chronic exposure to cobaltous
chloride caused adverse effects on fertility of male mice. Toxicology and Applied Pharmacology, 197(3):351
(abstract).
Holly RG (1955). Studies on iron and cobalt metabolism. J Am Med Assoc. 15:1349-52.
IARC (1991). Chlorinated drinking-water; chlorination by-products; some other halogenated compounds;
cobalt and cobalt compounds. Lyon, International Agency for Research on Cancer IARC Monographs on the
Evaluation of Carcinogenic Risks to Humans, Vol. 52).
IARC (2006). Metallic cobalt particles. In: Cobalt in hard-metals and cobalt sulphate, gallium arsenide,
indium phosphide and vanadium pentoxide. Lyon, International Agency for Research on Cancer IARC
Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 86).
Jensen AA, Tüchsen F. (1990). Cobalt exposure and cancer risk. Crit. Rev. Toxicol. 6:427-37.
Lison D (1994). Biological monitoring of workers exposed to cobalt metal, salt, oxides, and hard metal dust.
Occupational and Environmental Medicine 51:447-450
NTP (2002). NTP Executive Committee Working Group for the Report on Carcinogens (RG2) Commentary
on Human Exposure to Cobalt Sulphate.
http://ntp.niehs.nih.gov/ntp/newhomeroc/roc11/CoSO4Commentary.pdf
NTP (1991). Toxicity studies of cobalt sulphate heptahydrate (CAS No. 10026-24-1) in F344/N rats and
B6C3F1 mice (inhalation studies). Research Triangle Park, NC, United States Department of Health and
Human Services, National Institutes of Health, National Toxicology Program (NIH Publication No. 913124).
12
NTP (1998) Report on the toxicology and carcinogenesis studies of cobalt sulphate heptahydrate (CAS No.
10026-24-1) in F344/N rats and B6C3F1 mice (inhalation studies). Research Triangle Park, NC, United
States Department of Health and Human Services, National Institutes of Health, National Toxicology
Program (NIH Publication No. 471).
U.S., Department of Health and Human Services. National Toxicology Program. Report on carcinogens
(RoC) background document for cobalt sulphate. 2002.Available from:
http://ntp.niehs.nih.gov/ntp/newhomeroc/roc11/CoSO4Pub.pdf
Wehner AP, Busch RH, Olson RJ, Craig, DK. (1977). Chronic inhalation of cobalt oxide and cigarette
smoke by hamsters. Am. Ind. Hyg. Assoc. J. 38:338-346.
Wide, M. (1984) Effect of short-term exposure to five industrial metals on the embryonic and fetal
development of the mouse. Environ. Res., 33, 47-53
13
ANNEXES
14
1
ANNEX I: HUMAN HEALTH HAZARD ASSESSMENT
Information on the hazard properties of cobalt(II) sulphate is provided for information purposes
only as the classification has already been concluded by TC-C&L and included in Annex VI.
However, the C&L proposal and the data used for this are no longer available at the ECB website.
The provided information is limited to the endpoints relevant for identification as SVHC and is
based on available summaries.
The summaries used in this report are mainly copied from the ASTDR toxicological profile for
cobalt (published in 2004); the IARC monographs on the evaluation of carcinogenic risk to humans
for cobalt and cobalt compounds (Volume 52, published in 1991) and cobalt in hard metals and
cobalt sulphate (Volume 86, published in 2006); and the Report on Carcinogens (RoC) background
document for cobalt sulphate (published in 2002). The references are available in the ASTDR,
IARC and RoC.
Cobalt(II) sulphate is an inorganic salt of divalent cobalt. The behaviour of the anhydrous and
hydrated forms in solution is the same, as dissolution of either results in a system containing
hydrated ions and water. Many studies have investigated the carcinogenic, mutagenic and
reproductive toxicological effects of cobalt and cobalt compounds as a class including both
anhydrous and hydrate forms of cobalt(II) sulphate. These include a number of insoluble and
soluble cobalt compounds. The data from soluble cobalt(II) salts compounds can be used to read
across to cobalt(II) sulphate as relevant information concerning its CMR effects because these
properties are mediated by the ionic form of cobalt(II).
1.1
Toxicokinetics (absorption, metabolism, distribution and elimination)
1.1.1
Non-human information
1.1.2
Human information
The following summary on the toxicokinetics of cobalt and cobalt compounds was taken from the
RoC Background Document for Cobalt Sulphate, published in 2002. Information on the references
cited in this section (in parenthesis) can be found in the cited summary document.
Cobalt is absorbed from the gastrointestinal tract, lungs, and skin. Normal levels in blood and urine
in the general population are 0.2 to 2 µg/L, but concentrations greater than 200 µg/L have been
reported in the urine of workers occupationally exposed to cobalt (IARC 1991, NTP 1998).
Gastrointestinal tract absorption is highly variable depending on the compound, concentration, and
other factors, but is estimated to range from 5% to 45% (Lauwerys and Lison 1994) and may be
higher in females than in males (Christensen and Poulsen 1994). There is evidence that iron and
cobalt share the same transport mechanism in the duodenum (Léonard and Lauwerys 1990). The
degree of respiratory absorption in humans is unknown but varies with concentration. Some studies
have shown a good correlation between concentrations in air and concentrations in urine of workers
(Christensen and Poulsen 1994). Respiratory absorption of cobalt inhaled as cobalt oxide was about
30% (Lauwerys and Lison 1994). Scansetti et al. (1994) demonstrated substantial absorption of
cobalt through the skin.
15
Once absorbed, cobalt is preferentially distributed to the liver, kidney, and heart (Léonard and
Lauwerys 1990, Christensen and Poulsen 1994). Without occupational exposure, the cobalt content
in the adult human body is about 1 to 2 mg. The cobalt content of bone and muscle account for 14%
and 13%, respectively, of the total body burden, with the rest occurring in soft tissues (Léonard and
Lauwerys 1990, IARC 1991). The highest cobalt concentrations are in the liver, because vitamin
B12 is stored there; IARC (1991) reported that the cobalt concentration in the liver at autopsy
ranged from 6 to 151 µg/kg, with a median value of 30 µg/kg. Patients dying of cardiomyopathy
from excessive intake of cobalt-fortified beer had 10 times the normal amount of cobalt in the heart
(IARC 1991).
Concentrations of arsenic and cobalt were evaluated in tissue and plasma of patients with laryngeal
carcinoma (Collecchi et al. 1986). Plasma and histologically nonmalignant and malignant laryngeal
tissues were obtained from each of 15 male patients with no known exposure to toxic amounts of
cobalt. The cobalt concentrations in malignant laryngeal tissue (68.7 ± 7.3 ng/g dry weight, mean ±
SD) were significantly higher (P < 0.01, paired t-test and Wilcoxon’s test) than those in
nonmalignant laryngeal tissue (39.6 ± 7.0). The plasma cobalt concentrations were 25-fold higher in
the 15 patients with laryngeal carcinoma than in 11 apparently normal male individuals (18.27 ±
2.10 and 0.73 ± 0.10 ng/mL, respectively; P < 0.001, Student’s t-test and Mann-Whitney U-test).
Similar significant differences were reported for plasma and tissue arsenic levels. The authors
reported that further studies were in progress to ascertain the clinical significance of the changes in
tissue and plasma cobalt and arsenic concentrations; however, no additional publications on this
subject were identified in a search of the literature since 1986.
Cobalt is excreted in the urine and, to a lesser degree, in the feces. In experimental animals, 70% or
more is eliminated in the urine (IARC 1991). In humans, 28% to 56% of radiolabelled cobalt
chloride was eliminated in the urine and 2% to 12% in the feces within eight days after parental
administration. Between 9% and 16% of the administered dose was eliminated very slowly, with a
biological half-life of about two years (Smith et al. 1972). Thus, cobalt excretion has two distinct
phases: a rapid initial phase, with a half- life of a few days, followed by a slow second phase, with a
half-life of a year or more (Léonard and Lauwerys 1990, Lauwerys and Lison 1994). Cobalt
concentrations in the urine of workers in the Italian hard-metal industry were 10 to 100 µg/L at the
beginning of the work shift, increasing to 16 to 210 µg/L at the end of the shift (Sabbioni et
al.1994). Clearance from the lungs has not been studied but is expected to be rapid for soluble
cobalt salts (NTP 1998).
1.1.3
1.2
Summary and discussion on toxicokinetics
Acute toxicity
1.3
Irritation
1.4
Corrosivity
16
1.5
Sensitisation
1.6
Repeated dose toxicity
Not relevant for this type of dossier
1.7
Mutagenicity
1.7.1
1.7.1.1
In vitro data
The following summary was taken from the IARC monograph for Cobalt in hard-metals and cobalt
sulphate, published in 2006. Information on the references cited in this section (in parenthesis) can
be found in the cited summary document.
Cobalt sulphate has been shown to induce chromosomal aberrations and aneuploidy in plant cells
(Komczynski et al., 1963; Herich, R. 1965; Gori et al. 1957), chemical changes in bases in purified
calf thymus DNA and in isolated human chromatin in the presence of hydrogen peroxide, and
cytoskeletal perturbation of microtubules and microfilaments and p53 protein in mouse fibroblasts
treated in vitro. Cell transformation of Syrian hamster embryo cells has been induced by cobalt
sulphate in vitro.
A number of mammalian genes (metallothionein MT-IIA, heat-shock proteins hsp70, c-fos) are
transcriptionally regulated by a cis-acting DNA element located in their upstream regions. This
DNA element responds to various heavy metals, including cobalt, to stimulate the expression of
these genes (Murata et al., 1999). MT-IIA and hps70 but not c-fos RNA transcripts were increased
in HeLa S3 cells exposed to high concentrations of cobalt sulphate (> 10 µM). Metal response
element (MRE)-DNA binding activity was not inhibited by cobalt sulphate in Hela cells in vitro
while the results for heat shock element (HSE)-DNA binding activity were inconclusive. It is
unknown whether MT-IIA and hps70 induction plays a role in the pathophysiological processes
involved in cobalt carcinogenesis.
1.7.1.2
In vivo data
Molecular analysis of lung neoplasms of B6C3F1 mice exposed to cobalt sulphate heptahydrate
showed the presence of K-ras mutations with a much higher frequency (55%) of G > T transversion
at codon 12 than in controls (0%). This provides suggestive evidence that cobalt sulphate
heptahydrate may indirectly damage DNA by oxidative stress (NTP, 1998).
1.7.2
Human data
No studies are available specifically to cobalt(II) sulphate and its hydrates.
17
1.7.3
Other relevant information
1.7.3.1 In vitro and in vivo data
Several other cobalt(II) salts have been investigated in different short term tests for mutagenic
effects. The most studied is the water soluble cobalt(II) chloride. Few results are available for
other cobalt salts.
Mutagenicity effects for cobalt(II) chloride
a) In Vitro
Cobalt(II) chloride was found to be inactive in the λ prophage induction assay, and gave conflicting
results in the Bacillus subtilis rec+/– growth inhibition assay; when a cold preincubation procedure
was used, positive results were observed (Kanematsu et al.,1980). Lysogenic induction and phage
reactivation was found in Escherichia coli in the absence of magnesium. Also in E. coli, reduction
of fidelity of DNA replication by substitution of magnesium and inhibition of protein synthesis
were observed. Cobalt(II) chloride was inactive in all but two bacterial mutagenicity tests. One
study gave positive results in the absence, but not in the presence, of an exogenous metabolic
system, and in the second study, a preincubation procedure was used.
In bacteria, cobalt(II) chloride has been reported to reduce the incidence of spontaneous mutations
and to inhibit mutations induced by N-methyl-N′-nitrosoguanidine and 3-amino-1,4-dimethyl-5Hpyrido[4,3-b]indole. It was found to be comutagenic with several heteroaromatic compounds such
as benzo(a)pyrene and naphthylamine. In Saccharomyces cerevisiae, cobalt(II) chloride induced
gene conversion and petite ρ–mutation in mitochondrial DNA but not other types of mutation.
In mammalian cells cultured in vitro, positive results were obtained for induction of DNA–protein
cross-linkage, DNA strand breakage and sister chromatid exchange in most studies. Cobalt(II)
chloride induced mutations at the Hprt locus in Chinese hamster V79 cells, but not at the 8AG and
the Gpt loci. At the same Gpt locus in a transgenic Chinese hamster V79 G12 cell line, lower
concentrations of cobalt(II) chloride did induce gene mutations. In a single study, at the Tk locus in
mouse lymphoma L5178Y cells, the results were negative. In most studies, in cultured human cells
in vitro, positive results were obtained for inhibition of protein-DNA binding activities, inhibition
of p53 binding to DNA and for induction of gene expression, induction of DNA strand breakage
and sister chromatid exchange. Chromosomal aberrations were not observed in cultured human
cells (IARC,1991). Cobalt(II) chloride induced aneuploidy in cultured human lymphocytes.
b) In Vivo
In vivo, cobalt(II) chloride administered by intraperitoneal injection induced aneuploidy
(pseudodiploidy and hyperploidy) in bone marrow and testes of Syrian hamsters, micronuclei in
bone marrow in male BALB/c mice, and enhanced the micronuclei frequencies induced by the three
other mutagens tested. A gene expression mechanism is involved in several tissue and cellular
responses induced by soluble cobalt (generally cobalt chloride) mimicking the pathophysiological
response to hypoxia, a response which involves various genes including those coding for
erythropoiesis and for growth factors for angiogenesis (Gleadle et al., 1995; Steinbrech et al., 2000;
Beyersmann, 2002). Up-regulation of erythropoietin gene expression was observed in vivo after a
18
single intraperitoneal injection of cobalt chloride (60 mg/kg bw) into rats (Göpfert et al., 1995) and
might be of relevance in explaining the polyglobulia noted in humans treated with high doses of
cobalt (Curtis et al., 1976). In Chinese hamster ovary cells, cobalt also up-regulated the expression
of haeme oxygenase-1, a potent antioxidant and anti-inflammatory mediator which helps to
maintain cellular homeostasis in response to stress and injury (Gong et al., 2001). In studies
designed to explore the molecular mechanisms of gene response to hypoxia, cobalt (12 and 60
mg/kg bw as cobalt chloride) was found to up-regulate the expression of the PDGF-B gene in lungs
and kidneys of male Sprague-Dawley rats (Bucher et al., 1996). Since PDGF is an important growth
factor which modulates cell proliferation and the expression of several proto-oncogenes mainly in
mesenchymal cells, this effect of cobalt might explain how it may exert fibrogenic and/or
carcinogenic properties, but this remains to be documented.
Mutagenicity effects for other cobalt compounds
Cobalt sulphide particles were found to induce DNA strand breaks and alkali-labile sites in Chinese
hamster ovary cells. Data on the induction of gene mutations in Chinese hamster cells by cobalt
sulphide particles are conflicting. Cobalt sulphide was shown to induce morphological
transformation in Syrian hamster embryo cells; the crystalline form of cobalt sulphide being more
active than the amorphous form.
Cobalt(III) nitrate induced gene mutations in Pisum abyssinicum chlorophyll. Eight of 15 cobalt(III)
complexes with aromatic ligants were found to be positive in a DNA repair assay and four among
the eight were also mutagenic to Salmonella typhimurium. Cobalt(III) complexes with desferalinduced scission of double-stranded DNA, and a cobalt(III) Schiff-base complex induced inhibition
of zinc-finger transcription factors.
1.7.3.2 Human Data
Five studies have been conducted to date on the possible cytogenetic effects induced by cobalt
compounds in lymphocytes (or leukocytes) of individuals exposed to metals.
a) Sister chromatid exchange
Results of sister chromatid exchange have been obtained in two studies in which exposure was to a
mixture of metals. Occupational exposure to metals was studied by Gennart et al. (1993) who
determined sister chromatid exchange in 26 male workers exposed to cobalt, chromium, nickel and
iron dust in a factory producing metal powder and in 25 controls, who were clerical workers,
matched for age, smoking habits and alcohol consumption. Slight exposure to nickel or chromium
oxides could not be excluded, since, at one stage of the production process, the metals are melted in
an oven. The differences in the concentrations of cobalt in the urine in exposed persons (cobalt
geometric mean, 23.6 µg/g creatinine; range, 6.4–173.1) and controls (cobalt geometric mean,.1
µg/g creatinine; range, 0.2–3.2) were statistically significant. Analysis of variance revealed that
both exposure status (exposed versus controls) and smoking habits (smokers and former smokers
19
versus never smokers) had statistically-significant effects on the sister chromatid exchange or highfrequency cell (HFC) rank values. These effects may not be attributable to cobalt alone.
Stea et al. (2000) compared sister chromatid exchange in patients who had chrome–cobalt alloy
prostheses and in those with other metal alloys. The study population consisted of 30 patients with
joint prostheses and 17 control subjects matched for age, sex, and exposure to occupational and
environmental risk factors such as chemicals, antineoplastic drugs and traffic smog. The mean
sister chromatid exchange rate in subjects with prostheses (5.2 ± 1.5) was not statistically different
from that in subjects without prostheses (4.4 ± 1.3). Subjects with titanium–aluminium–vanadium
alloy prostheses had a significantly higher sister chromatid exchange frequency (6.3 ± 2.3) than the
controls (4.4 ± 1.3) whereas subjects with prostheses made of chrome–cobalt alloys or mixed
prostheses had a higher, but not significantly, sister chromatid exchange frequency (4.7 ± 1.1 and
5.0 ± 2.1, respectively) than the controls. The number of sister chromatid exchanges was not
affected by the presence of bone-cement used in prosthesis fixation nor by duration of the implant.
There was no difference in the incidence of sister chromatid exchange between the two populations
(those with prostheses and controls) considered globally and the considered risk factors, including
smoking. The HFC values (> 9 exchanges per cell) were also recorded. Among the cases studied,
three patients with implants (one with a prosthesis made of chrome–cobalt alloy and two with
mixed prostheses) showed markedly elevated percentages of HFCs (> 10%). It was concluded that
the indication of possible cytogenetic damage in the patient populations should be considered with
caution, since the sample population was small.
b) Micronuclei and DNA damage
Burgaz et al. (2002) applied the micronucleus test to assess the effect of occupational exposure to
metal alloys in both exfoliated nasal cells, and in vitro in lymphocytes. The groups studied
consisted of 27 male dental laboratory technicians exposed to metal alloys (35–65% cobalt, 20–30%
chromium, (0–30% nickel) in dental laboratories during the production of skeletal prostheses, and
15 male controls from the faculty of pharmacy. In the exposed group, a significant correlation was
found between urinary cobalt concentrations and frequencies of micronuclei in nasal cells, but not
in lymphocytes. The results of multifactorial variance analysis revealed that occupational exposure
was the only factor that significantly influenced the induction of micronuclei.
The possible genotoxic effects of occupational exposure to cobalt alone or to hard-metal dust was
explored in a study using the in-vitro cytochalasin-B micronucleus test in lymphocytes as end-point
for mutations (De Boeck et al., 2000). The authors concluded that workers exposed solely to
cobalt-containing dust at TLV/TWA (20µg cobalt/g creatinine in urine, equivalent to TWA
exposure to 20 µg/m3) did not show increased genotoxic effects but that workers who smoked and
were exposed to hard-metal dusts form a specific occupational group which needs closer medical
surveillance.
Hengstler et al. (2003) concluded from a study of workers co-exposed to cadmium, cobalt, lead and
other heavy metals, that such mixed exposure may have genotoxic effects. The authors determined
DNA single-strand break induction by the alkaline elution method in cryopreserved mononuclear
blood cells of 78 individuals co-exposed to cadmium (range of concentrations in air, 0.05–138
µg/m3), cobalt (range, 0–10 µg/m3) and lead (range, 0–125 µg/m3) and of 22 subjects without
occupational exposure to heavy metals (control group). Some concerns about the study were
addressed by Kirsch-Volders and Lison (2003) who concluded that it did not provide convincing
evidence to support the alarming conclusion of Hengstler et al. (2003).
20
1.7.4
Summary and discussion of mutagenicity
The results of genotoxicity assays for cobalt(II) sulphate along with a variety of cobalt(II) salts
demonstrate the mutagenic potential of these salts both in vitro and in vivo. Cobalt, in salts with a
valence state of +2, was mostly negative in mutagenicity tests conducted in Salmonella
typhimurium, Escherichia coli, and yeast, but weakly positive in Bacillus subtilis. In mammalian
test systems, many cobalt compounds and metals are genotoxic. Cobalt compounds and cobalt
metals have been reported to cause clastogenic effects in mammalian cells such as human
lymphocytes, transformation in hamster cells, sister chromatid exchanges in human lymphocytes,
and micronucleus formation in mouse bone marrow cells and human lymphocytes. It has also been
demonstrated to induce micronuclei in vivo (bone marrow in mice).
TC-C&L concluded on the then available data after discussions in November 2003, May 2004 and
September 2004 that cobalt(II) sulphate and cobalt(II) sulphate heptahydrate should be classified
with R68 (summary record ECBI/139/04 rev.2).
1.8
Carcinogenicity
1.8.1
1.8.1.1
Carcinogenicity: oral
No carcinogenicity studies were available using the oral route of exposure.
1.8.1.2
Carcinogenicity: inhalation
The NTP (1998) conducted a two year inhalation carcinogenicity study of cobalt sulphate
heptahydrate (a soluble cobalt salt) with mice and rats. The hydrated and non-hydrated forms of a
solute will behave similarly when dissolved in water, forming both a solution of hydrated ions and
water (RoC, 2004). These studies and results are summarized below.
The following information was taken from the RoC Background Document for Cobalt Sulphate, for
Cobalt, published in 2002. Information on the references cited in this section (in parenthesis) and
Annex II can be found in the cited summary document.
NTP carcinogenicity bioassay in mice
Groups of six-week-old B6C3F1 mice (50 of each sex) were administered cobalt sulphate
heptahydrate aerosols by inhalation at target concentrations of 0, 0.3, 1.0, or 3.0 mg/m3, 6 h/day, 3
days/week, for 105 weeks (NTP 1998, Bucher et al. 19998). The corresponding concentrations
expressed as elemental cobalt were 0, 0.063 mg/m3, 0.210 mg/m3, and 0.628 mg/m3. Exposure
concentrations were based on previous subacute and subchronic studies (Bucher et al. 1990, NTP
1991). Cobalt sulphate heptahydrate was generated and delivered from an aqueous solution via a
compressed-air-driven nebulizer, an aerosol charge neutralizer, and an aerosol distribution system.
The aerosol was dried and mixed with humidified air before delivery to the inhalation chambers,
8
It should be noted that the article referring to, Bucher et al. 1999, reports the test substance to be cobalt sulphate
hexahydrate.
21
thus allowing partial rehydration of the aerosol particles. The mass median aerosol particle diameter
was 1 to 3 µm, and the aerosol consisted of 1 mole of cobalt, 1 mole of sulphate, and 5.9 moles of
water per mole of aerosolized cobalt sulphate (Bucher et al. 1999). The overall chemical purity of
the study material was reported to be 99%. Survival was not significantly affected by exposure.
Mean body weights were slightly higher in exposed females than in controls, and mean body
weights were lower in the high-dose males than in controls from week 96 to the end of the study.
The incidences of alveolar/bronchiolar adenoma, alveolar/bronchiolar carcinoma, and
alveolar/bronchiolar adenoma or carcinoma (combined) showed a positive exposure response trend
in all groups. The incidences of these neoplasms were significantly higher in all the high-dose
groups than in the controls, as was the incidence of adenoma or carcinoma (combined) in mid-dose
female mice. The NTP (1998) concluded that there was clear evidence of carcinogenic activity in
both male and female mice, based on increased incidences of lung tumors. Although the incidence
of hemangiosarcoma was significantly increased in male mice in the mid-dose group, Helicobacter
hepaticus infection was present in these mice, making interpretation of this finding difficult. Liver
sections from several male mice were positive for bacteria, and the spectrum of liver lesions in
these mice was consistent with H. hepaticus infection.
In addition to the neoplastic lesions, exposure to cobalt sulphate induced a spectrum of
inflammatory, fibrotic, and proliferative lesions in other portions of the respiratory tract that were
consistent with results observed in the shorter-term studies . These included hyperplasia of the
olfactory epithelium (high-dose groups), squamous metaplasia of the larynx (all exposed groups),
cytoplasmic vacuolization of the bronchi (all exposed groups), diffuse histiocytic cell infiltration
(high-dose males), and focal histiocytic cell infiltration of the lung (high-dose females). Histiocytic
infiltration was observed most often in lungs with alveolar/bronchiolar neoplasms and was
attributed to the neoplasms, rather than to a direct effect of cobalt sulphate.
NTP carcinogenicity bioassay in rats
Groups of six-week-old F344/N rats (50 of each sex) were administered cobalt sulphate
heptahydrate aerosols by inhalation at target concentrations of 0, 0.3, 1.0, or 3.0 mg/m3, 6 h/day, 5
days/week, for 105 weeks (NTP 1998, Bucher et al. 1999). Exposure concentrations were based on
previous subacute and subchronic studies (Bucher et al.1990, NTP 1991). Survival of exposed rats
did not differ significantly from that of controls. Among males, survival was 34%, 30%, 42%, and
30% in the control, low exposure, mid-exposure, and high-exposure groups, respectively. Overall,
survival was higher in females than in males, at 56%, 51%, 52%, and 60% in the control, low
exposure, mid-exposure, and high-exposure groups, respectively. Mean body weights in all exposed
groups did not differ significantly from those of controls throughout the study). The incidence of
alveolar/bronchiolar adenoma or carcinoma (combined) showed a significant positive exposurerelated trend in male rats and was significantly higher in the high-dose group than in the control
group. A significant positive exposure-related trend for alveolar adenoma, carcinoma, and adenoma
or carcinoma (combined) was observed in female rats, and incidences were significantly higher in
the mid-dose and high-dose groups than in the controls. In addition, squamous-cell carcinoma of the
lung was observed in two female rats (one each in the mid-dose and high-dose groups). The
incidence of benign adrenal pheochromocytoma was increased in high-dose females, and the
incidence of benign, complex, or malignant pheochromocytoma (combined) was increased in middose males and high-dose females. The increased incidences in the high-dose females were
considered to be exposure related. The NTP (1998) concluded that there was some evidence of
carcinogenicity in male rats, based on increased incidences of alveolar/bronchiolar neoplasms.
Marginal increases in adrenal medullary tumors in male rats may have been related to exposure to
cobalt sulphate heptahydrate. There was clear evidence of carcinogenicity in female rats, based on
22
increased incidences of alveolar/bronchiolar neoplasms and pheochromocytoma of the adrenal
medulla.
Nonneoplastic lesions of the respiratory tract generally were more severe in rats than in mice.
Significantly increased incidences of inflammatory, fibrotic, and proliferative lesions were observed
in all dose groups in the lung (hyperplasia and metaplasia of the alveolar epithelium, granulomatous
inflammation, interstitial fibrosis, and proteinosis), nose (lateral wall hyperplasia and olfactory
epithelium atrophy), and larynx (squamous metaplasia of the epiglottis). The NTP characterized all
fibroproliferative lesions as atypical hyperplasia. Several animals had malignant neoplasms with a
very prominent fibrous component, some of which presumably had progressed from atypical
hyperplasia. The NTP (1998) concluded that it was clear that all the morphologic variants of
proliferative lesions represented a response to cobalt sulphate heptahydrate.
Summary of NTP carcinogenicity in mice and rats
Under the conditions of these 2-year inhalation studies there was some evidence of carcinogenicity
of cobalt sulphate in male F344/N rats based on increase incidences of alveolar/bronchiolar
neoplasms. Marginal increase of pheochromocytomas of the adrenal medulla may have been
related to exposure to cobalt sulphate heptahydrate. There was clear evidence of the carcinogenic
activity in female F344/N rats based on incidences of alveolar/bronchiolar neoplasms and
pheochromocytomas of the adrenal medulla in groups exposed to cobalt sulphate heptahydrate.
There was clear evidence of carcinogenic activity of cobalt sulphate heptahydrate in male and
female B6C3f1 mice base on increase incidences of alveolar/bronchiolar neoplasms.
1.8.1.3
Carcinogenicity: dermal
No carcinogenic studies were available using the dermal route of exposure.
1.8.2
Human information
No studies are available specifically to cobalt(II) sulphate and its hydrates in humans.
1.8.3
1.8.3.1 In vivo data
Other cobalt compounds
Syrian golden hamsters (51 per group) exposed by inhalation (as cobalt oxide) at 10.0 mg/m3 for
7h/day, 5 days/week, for a lifetime developed emphysema, but the incidence of pulmonary tumors
was not different from controls. While tobacco smoke exposure induced pulmonary tumors in
14/51 animals, the incidence in animals exposed to both tobacco smoke and cobalt oxide was 11/51
(Wehner et al., 1977).
Different forms of cobalt (pieces, powder, alloy particles, soluble and insoluble salts) have been
investigated for possible carcinogenic effects in long-term animal experiments with rabbits, rats,
mice, hamster and guinea-pigs. Several routes of administration of the compound have been used,
23
but mainly intramuscular injections (Jensen A.A, & Tüchsen, F., 1990). See Annex II for a
summary of the results.
1.8.3.2 Human data
Several epidemiological studies addressing cancer risk in the hard-metal and cobalt production
industry have been reported.
The following information was taken from the RoC Background Document for Cobalt Sulphate, for
Cobalt, published in 2002. Information on the references cited in this section (in parenthesis) can
Hard-metal industry
Four mortality studies of the hard-metal industry have been conducted in Sweden and France. Most
of these studies investigated the effects of occupational exposure to hard metals (cobalt and
tungsten) or metallic cobalt (Hogstedt et al. 2000, Lasfargues et al. 1994, Moulin et al. 1998, Wild
et al. 2000; reported in IARC 2006). These studies have reported increases in lung cancer from
occupational inhalation exposure to hard metal.
Hogstedt & Alexandersson (1990) reported on 3163 male workers, each with at least 1 year of
occupational exposure at hard metal manufacturing plants in Sweden during 1940–1982 and
followed from 1951 to 1982. Exposures included a number of other substances used in the
production of hard metal, such as tungsten carbide. The lung cancer SMR was 1.34 (95% CI =
0.77–2.13); the all-cause mortality SMR was slightly less than unity. Among workers with more
than 10 years of employment and more than 20 years since first exposure, a significant excess of
lung cancer mortality was observed (SMR = 2.78, 95% CI = 1.11–5.72). Smoking habits among
hard metal workers were reported to be similar to those of the male Swedish population.
Lasfargues et al. (1994) conducted a cohort mortality study of 709 male workers employed for >1
year at a hard metal manufacturing plant (including two workshops) in central France. Follow-up
was from 1956 to 1989. Categories of exposure were defined based on dust and urinary
measurements of cobalt taken in 1983. Workers who had been employed in jobs with different
degrees of exposure were categorized according to their highest exposure. Job histories were
obtained from company records; before 1970, however, the records were often missing. The overall
mortality did not differ from expected (SMR = 1.05, 95% CI = 0.82–1.31). Mortality due to lung
cancer was in excess (SMR = 2.13, 95% CI = 1.02–3.93), and the excess was highest among
workers in the areas with highest exposures to cobalt (SMR = 5.03, 95% CI = 1.85–10.95).
An industry-wide cohort mortality study of the French hard metal industry was conducted by
Moulin et al. (1998) to further evaluate the potential association of lung cancer risk with
occupational exposure to cobalt and tungsten carbide. The cohort included 5777 men and 1682
women (total = 7459 workers) from 10 factories (most of which were in eastern France), including
the factory studied by Lasfargues et al. (1994). The all-cause mortality SMR was 0.93; the lung
cancer SMR was 1.30 (95% CI = 1.00–1.66). Sixty-one of the 63 lung cancer deaths in the cohort
were included in a nested case–control study. Three controls that were alive on the date the case
died were matched to each case based on gender and age. Occupational exposure of the cases and
controls was evaluated based on a job–exposure matrix involving 320 job periods and exposure
intensity scores from 0 to 9. Data on smoking were available for 80% of the cases and controls. The
odds ratio for workers exposed to cobalt and tungsten carbide was 1.93 (95% CI = 1.03–3.62) for
exposure levels 2–9 versus levels 0–1. The odds ratio for cobalt with tungsten carbide increased
24
with duration of exposure and cumulative dose, but less so for level of exposure. Adjustments for
exposure to known or suspected carcinogens and smoking did not change the results.
A study of the largest plant in the multicentre cohort of Moulin et al. (1998) was conducted by Wild
et al. (2000). The authors used the same job–exposure matrix of Moulin et al. (1998) but made use
of the more detailed job histories available. Follow-up was from 1968 to 1992. The SMR for the allcause mortality was 1.02 (95% CI = 0.92–1.13). The SMR for lung cancer among men was
increased (SMR = 1.70, 95% CI = 1.24–2.26). The lung cancer SMR for exposure to hard metal
dust at an intensity score of >2 was 2.02 (95% CI = 1.32–2.96). In a Poisson regression model
including terms for smoking and other occupational carcinogens, the risk for lung cancer increased
with duration of exposure to cobalt with tungsten before sintering; there was no evidence of risk
from exposure to sintered hard metal dust.
Cobalt production industry
Moulin et al. (1993) studied the mortality of a cohort of 1148 workers in a cobalt electrochemical
plant in France that produced cobalt and sodium by electrochemistry, extending the follow-up of an
earlier study by Mur et al. (1987; reported in IARC 1991). The cohort included all men who had
worked at the plant for a minimum of 1 year between 1950 and 1980. Follow-up was to the end of
1988 and was obtained for 99% of French-born workers. Because of difficulty in follow-up of nonFrench workers, results were presented only for the 870 French-born (i.e. a loss to follow-up of
24%). The SMR for all causes of death was 0.95 (95% CI = 0.78–1.26). The SMR for lung cancer
was 1.16 (95% CI = 0.24–3.40) among workers exclusively employed in cobalt production and 1.18
(95% CI = 0.32–3.03) for workers ever employed in cobalt production.
Other cobalt compounds
Tüchsen et al. (1996) did not find evidence of an increased risk of lung cancer among a cohort of
874 women occupationally exposed to poorly soluble cobalt–aluminate spinel in two porcelain
production factories in Denmark compared with that expected based on national rates for Danish
women.
Summary on human data
Available studies of the carcinogenic effects of cobalt in occupationally-exposed humans have
reported mixed results, with both positive and negative results. Several studies of hard metals
(cobalt and tungsten carbide) exposure to humans (Lasfargues et al. 1994; Moulin et al. 1998; Wild
et al. 2000) have reported increases in lung cancer from occupational inhalation exposure to hard
metal (ASTDR, 2004). Even though these studies consistently reported an increased risk of lung
cancer among workers exposed to cobalt, the workers were also exposed to other agents (e.g.,
tungsten carbide) and probably were not exposed to soluble cobalt (Report on Carcinogens, 2004).
Thus, it is difficult to ascertain whether the increased incidence of lung cancer is attributable to
cobalt. Only one study investigated the effects of exposure to cobalt salts. The initial study reported
an increased risk of lung cancer among cobalt production workers, but a follow-up study of the
same workers found no increased risk of cancer (Mur et al. 1987, Moulin et al. 1993). Interpretation
of this finding is limited by the small number of exposed workers who developed cancer.
The IARC in volume 52 (1991) reviewed the carcinogenic risk to humans of cobalt and cobalt
compounds and concluded the evidence of carcinogenicity was inadequate.
1.8.3.3 IARC assessments
The IARC has classified cobalt and cobalt compounds as possibly carcinogenic to humans (Group
2B) based on sufficient evidence that cobalt metal powder and cobaltous oxide are carcinogenic in
25
animals (IARC, 1991). The IARC recently (2006) classified cobalt metal with tungsten carbide as
probably carcinogenic to humans (Group 2A). Cobalt metal without tungsten carbide and cobalt
sulphate and soluble cobalt(II) salts were classified as possibly carcinogenic to humans (Group 2B)
(IARC, 2006). This was based on sufficient evidence in experimental animals for the
carcinogenicity of cobalt sulphate and cobalt metal powder
1.8.4
Summary and discussion of carcinogenicity
Lifetime inhalation of cobalt(II)sulphate resulted in increased tumor incidences in both rats and
mice; NTP reported that there was some evidence of carcinogenicity in male Fischer 344 (F344)
strain rats, and clear evidence of carcinogenicity in female F344 strain rats and male and female
B6C3F1 strain mice following inhalation exposure. Oral and dermal data on the carcinogenic
effects of cobalt and cobalt compounds are not available.
1.9
Toxicity for reproduction
1.9.1
Effects on fertility
1.9.1.1
The following information was taken from the ASTDR Toxicological profile for cobalt, published in
2004. Information on the references cited in this section (in parenthesis) can be found in the cited
summary document.
In animals, long-term exposure to cobalt-containing aerosols has resulted in effects on reproductive
end points (see section 5.8.2). Testicular atrophy was reported in rats, but not in mice, exposed to 19
mg cobalt/m3 as cobalt sulphate over 16 days (Bucher et al. 1990; NTP 1991). Following exposure
of mice to cobalt (as cobalt sulphate) for 13 weeks, a decrease in sperm motility was found at 1.14
mg cobalt/m3, and testicular atrophy was found at 11.4 mg cobalt/m3. A significant increase in the
length of the estrous cycle was reported in female mice exposed to 11.4 mg cobalt/m3 for 13 weeks
(Bucher et al. 1990; NTP 1991). No effects on the male or female reproductive systems were
observed in rats similarly treated for 13 weeks (Bucher et al. 1990; NTP 1991), or in mice or rats
exposed to up to 1.14 mg cobalt/m3 for 104 weeks (Bucher et al. 1999; NTP 1998).
1.9.1.2
Human information
No human studies were available specifically to cobalt(II) sulphate and its hydrates regarding
fertility and developmental effects in humans. There is some information available however of
human exposure to cobalt (as cobalt chloride) see section 1.9.3.2.
26
1.9.2
1.9.2.1 Effects on fertility
Several studies have been conducted with soluble cobalt compounds to explore their potential effect
on fertility.
summary document.
Testicular degeneration and atrophy have been reported in rats exposed to 13.3–58.9 mg
cobalt/kg/day as cobalt chloride for 2–3 months in the diet or drinking water (Corrier et al. 1985;
Domingo et al. 1984; Mollenhauer et al. 1985; Nation et al. 1983; Pedigo and Vernon 1993; Pedigo
et al. 1988), or in mice exposed to 43.4 mg cobalt/kg/day as cobalt chloride for 13 weeks in the
drinking water (Anderson et al. 1992, 1993). Pedigo and Vernon (1993) reported that cobalt
dichloride (400 ppm in drinking water for 10 weeks) increased pre-implantation losses per pregnant
female in the dominant lethal assay by compromising the fertility of treated male mice.
Other publications
In an abstract reported by Elbetieha et al. (2004), sexually mature male mice exposed to cobalt(II)
chloride at 200, 400, or 800 mg/l in their drinking-water for 12 weeks were assessed for effects on
fertility by breeding these exposed males to unexposed females. Fertility, as measured by successful
matings, was reduced in mice exposed to cobalt chloride at 400 and 800 mg/l (internal doses of
46.91± 4.78 and 93.01 ± 6.76 mg/kg body weight per day, respectively). The number of
implantation sites was significantly reduced in females mated with exposed males at 400 and 800
mg/l. The number of viable fetuses was decreased in females mated with males at all three exposure
levels. In the 800 mg/l males, absolute epididymal weight was significantly decreased, whereas
relative and absolute testes weights were decreased in males exposed to both 400 and 800 mg/l.
Epididymal sperm count was decreased in males of all three exposure levels. At 400 and 800 mg/l,
males also exhibited reduced testicular sperm counts and daily sperm production. The testes
displayed severe abnormalities, including hypertrophy of the interstitial Leydig cells, congested
blood vessels, degeneration of the spermatogonial cells, and necrosis of seminiferous tubules and
interstitial tissue.
1.9.3
1.9.3.1
Developmental toxicity
summary document.
Szakmary et al. (2001) reported that exposure of pregnant rats to 0–38 mg Co/kg-day as cobalt
sulphate did not result in changes in fetal death rates, maternal body weigh gain, average litter size,
or average fetal or placental weights; however, a dose-related trend was seen for the percent of
fetuses with retarded body weights. In contrast, no effects on fetal growth or survival were found
following exposure of rats to 24.8 mg cobalt/kg/day as cobalt chloride during gestation days 6–15
(Paternian et al. 1988). In mice, exposure to 81.7 mg cobalt/kg/day as cobalt chloride during
27
gestation days 8–12 was reported to have no effect on fetal growth or mortality in mice (Seidenberg
et al. 1986). In a later mouse study that exposed pregnant mice to 19 mg Co/kg-day as cobalt
sulphate, no changes in litter size, postimplantation loss, or average fetal or placental weights were
seen; the only difference seen was an increase in the percent of fetuses with retarded body weights
(Szakmary et al. 2001). The same study reported that rabbits exposed to ≥ 38 mg Co/kg-day, as
cobalt sulphate, showed nearly complete maternal lethality, and complete fetal loss. Rabbits
exposed to 7.6 mg Co/kg, as cobalt sulphate, showed significant increases in mortality and fetal
resorption, as well as an increase in fetuses with retarded body weight (Szakmary et al. 2001)
1.9.3.2
Human information
No developmental effects on human fetuses were observed following treatment of pregnant women
with cobalt chloride to raise hematocrit and hemoglobin levels that are often depressed during
pregnancy. Dosages up to 0.6 mg cobalt/kg/day for 90 days were given (Holly 1955). Examination
of the fetuses, however, was limited to the reporting of obvious birth defects, and exposure only
occurred in the final trimester (ASTDR, 2004)
1.9.4 Other relevant information
1.9.4.1 Developmental toxicity
Several studies have been conducted with soluble cobalt compounds to explore their potential effect
on development.
summary document.
Oral exposure of female rats to cobalt chloride at 5.4 or 21.8 mg cobalt/kg/day from gestation day
14 through lactation day 21 has been shown to result in stunted growth and decreased survival,
respectively, of newborn pups (Domingo et al. 1985b). The effects on the offspring occurred at
levels that also caused maternal toxicity (reduced body weight and food consumption, and altered
hematological measurements) and might therefore have been an indirect effect of maternal toxicity
rather than a direct effect of cobalt on the fetus (Domingo et al. 1985b). Teratogenic effects were
not observed.
Other publications
Wide (1984) reported that a single intravenous injection of cobalt chloride hexahydrate into
pregnant NMRI mice (5 mM per animal in the tail vein; [120 µg/animal]) on day 8 of gestation
significantly affected fetal development (71% of skeletal malformations versus 30% in controls); in
animals injected at day 3 of gestation, no interference with implantation was noted. In the same
experiment but replacing cobalt chloride by tungstate (25 mM of W per animal; [460 µg/animal]) a
significant increase in the number of resorptions was observed (19% versus 7% in controls), but no
skeletal malformations (RoC, 2006).
Paksy et al. (1999) found that in-vitro incubation of postblastocyst mouse embryos with cobalt(II)
ions (as cobalt sulphate) adversely affected the development stages at a concentration of 100 µM
and decreased the trophoblast area (at a concentration of 10 µM) (ASDTR, 2004).
28
1.9.5
Summary and discussion of reproductive toxicity
Effects on male and female sexual function were observed after repeated inhalatory exposure of rats
and mice. Mice and rats exposed to high oral doses of cobalt dichloride for 2-3 months experience
testicular degeneration and atrophy and reduced fertility. Stunted growth and decreased survival
were observed among newborn rats at dose levels that also caused maternal toxicity in one study.
Similar doses did not produce such effects in another study of rats or in a study of mice. Rabbits
exposed at high doses were found to have increased mortality, fetal resorption, and number of
fetuses with decreased body weight. No teratogenic effects were reported in any of the studies.
1.10
Other effects
29
2
ANNEX II: ANIMAL CARCINOGENICITY AND RELATED EFFECTS DATA OF OTHER COBALT COMPOUNDS.
Reference
Species/
Strain
Sex
Dose Schedule
Experimental parameter/observation
Group
Comments
0
1
2
Dose (mg)
Survival (122 weeks)
Local sarcoma
0
Not given
0/10
28
Dose (mg)
Survival (122 weeks)
Local sarcoma
0
Not given
0/10
28
28
5/10
8/10
3
Cobalt metal powder
Heath (1954a, 1956)
Rat
Hooded
M
i.m. single inj.
fowl serum
F
Health & Daniel
(1962)
Rat
Hooded
F
intrathoracic in serum
Dose (mg)
Survival (3 days)
Thoracic tumour
0
28
12/20
4/12
Jasmin & Riopelle
(1976)
Rat
SpragueDawley
F
intrarenal
Dose (mg)
Survival (12 months)
Kidney tumour
0
Not given
0/16
5
Rat
Hooded
F
i.m. single inj., wear
particles from Co/Cr/Mo in
horse serum
Dose (mg)
Local sarcoma
0
Not given
28
i.m. impl.
Co/Cr/W/Ni/C/Mn/Si/Fe
(1.6 x 8 mm)
Dose (polished rod)
Survival (2 years)
Local tumour
0a
Not given
0/30
Inadequate
0/18
Cobalt alloys
Heath et al. (1971);
Swanson et al. (1973)
Gaechter et al. (1977)
Memoli et al. (1986)
Memoli et al. (1960)
Cobalt alloys (contd)
30
Rat
SpragueDawley
Rat
SpragueDawley
Rat
Wister
M+F
M+F
M+F
Intraoss. impl.,
Co/Cr/Ni/Mo/W/Zr
s.c. impl. Co/Cr/Mo/Ni
Dose (powder, wire, rod)
Local sarcoma
Dose (pellets-2mm diam)
Local sarcoma
23/80
0
a
0a
1
0/30
0/90
0
a
Not given
0/51
0/26
Not given
0/10
1
7/76b
Not significant
difference in
distant tumours
Reference
Meachim et al. (1982)
Species/
Strain
Dose Schedule
Group
Comments
0
1
2
3
28
7/61
0
28
0/53
0
F
i.m. impl. Co/Cr/Mo fine and Dose (mg)
coarse particles
Survival (2 years)
Local tumour
0
5/50
0
28
11/51
0
Steinhoff &Mohr (1991) Rat
SpragueDawley
M+F
3 i.p ijn., Co/Al/Cr spinel
powder
0
Not given
1/20
200
SpragueDawley
M+F
Intratracheal inst.
Dose (mg/kg bw)
1 x 2 weeks Co/Al/Cr spinel Survival (2 years)
2 years
Squamous-cell tumour of the lung
0
Not given
0/200
10
Meachim et al. (1982)
Rat
Wistar and
hooded
Sex
Dose (mg/kg bw)
Survival (2 years)
Local tumour
2/20
3/100
Guinea-pig F
i.m. impl. Co/Cr/Mo powder Dose (mg)
Survival (3 years)
Local tumour
Local fibroblastis hyperplasia
28
12/46
0/46
8/46
Mouse
Swiss
F
i.m. inj., in each thigh
Dose (mg/site)
Survival (13 weeks)
Local tumour sarcoma
0
48/51
0/48
10
46/75
0/46
M
Intratracheal inst.
1 x 2 weeks
2 years
Dose (mg/kg bw)
Survival (2 years)
Benign squamous pulmonary tumour
Bronchiolalveolar adenoma
Pulmonary adenocarcinoma
Bronchalveolar adenocarcinoma
0
Not given
0/100
0/100
0/100
0/100
2
10
1/50
0/50
0/50
0/50
0/50
2/50
2/50
1/50
Dose (mg/kg bw)
Survival (2 years)
Bronchiolalveolar adenoma
Bronchalveolar adenocarcinoma
0
Not given
0/100
0/100
2
10
1/50
0/50
0/50
1/50
0
10/10
0/10
30
10/10
5/10
Cobalt[II] oxide
Gilman & Ruckerbuaer
(1962)
SpragueDawley
F
Gilman & Ruckerbuaer
(1962)
Rat Wistar
M+F
i.m. inj.
Dose (mg/site)
Survival (90 days)
Local sarcoma
Gilman (1962)
Rat Wistar
M+F
i.m. inj.
Dose (mg/site)
Survival (13 weeks)
Local sarcoma
M
s.c. inj.
Dose (mg/kg bw)
20
24/32
13/29 sites
Cobalt[II] oxide (contd)
0
2
10
31
Reference
Species/
Strain
Sex
SpragueDawley
SpragueDawley
Wehner et al. (1977)
M+F
Dose Schedule
Group
Comments
0
1
2
5/10
4/10
2 mg/kg bw 5/weeks or
10 mg/kg bw 1/week for
2 years
Survival (2 years)
Local malignant tumour
Not given
0/20
3 i.p. inj. at 2-month
intervals
Total dose (mg/kg bw)
Survival (2 years)
Local malignant tumour
0
Not given
1/20
200
0
7/51
0/51
0/51
0/51
0/51
1/51
200
9/51
1/51
1/51
0/51
0/51
0/51
3
3
14/20
Hamster
ENG:ELA
M
Inhalation
7h/day
5d/week
for life
Dose (mg/m )
Reticulum-cell sarcoma
Carcinoma
Lymphosarcoma
Leukaemia
Plasma cell tumour
Gilman (1962)
Rat Wistar
M+F
i.m. inj.
Dose (mg/site)
Survival (13 weeks)
Local sarcoma
Jasmin & Riopelle
(1976)
Rat
SpragueDawley
F
intrarenal
Dose (mg)
Kidney tumour
0
Not given
0/16
5
Rat Wistar
M
Dose (mg/kg bw)
Survivalc
Subcutaneous sarcoma
0
19/20
0/19
40
11/20
8/11
0.2
No statistical
difference
Cobalt [II] sulphide
20
29/30
35/58 sites
Inadequate
0/20
Cobalt[II] chloride
Shabaan et al. (1977)
s.c. 2 x 5 day,
9-d interval
40
16/20
6/16
p < 0.001
(Fisher exact test)
Cobalt naphthenate
Nowak (1966)
Mouse
NS
NS
i.m. inj.
NS
Dose (mg)
Survival
Tumour of the striated muscle
0
Nowak (1961)
Rabbit
M
i.m.
i.v.
i. pleural
i. hepatic
Dose unspecified
0
5
1
1
1
Mouse
M+F
i.p. inj.
Total dose (mg/kg bw)
0
95
Inadequate
8/30
Inadequate
Cobalt [III] acetate
Stoner et al. (1976)
32
237
475
Not significant
Reference
Species/
Strain
Strain A
Sex
Dose Schedule
3/week, 24 doses
Survival (30 weeks)
Pulmonary tumour
Group
Comments
0
1
2
3
19/20
7/19
20/20
8/20
20/20
8/20
17/20
10/17
a
group 0, untreated; group 1, sham-treated; bPowder, 1/18 sarcoma; MP35N, 3/26 sarcomas; compacted wire, 3/32 sarcomas; c2 months for groups 0 and 1; at 8 months for
group 2; NS, not specified.
i.m., intramuscular; inj, injection; impl., implantation; intraoss, intra-osseous; s.c., subcutaneous; inst., instillation; i.p., intraperitoneally, i.v., intravenous
33

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Publikation WATN Kiel 2009